(a) Field of the Invention
The present invention relates to an interference cancellation receiving method for an orthogonal frequency division multiple access (OFDMA)-based mobile communication system, and an apparatus using the same. More particularly, it relates to a method for canceling interference from a neighboring base station or a remote base station when a mobile station located in a cell boundary area receives a data signal from a serving base station in an orthogonal frequency division multiplexing access (OFDMA) mobile communication system.
(b) Description of the Related Art
Regarding signal transmission between a base station and a mobile station in an orthogonal frequency division multiple access (OFDMA) system based on the wideband wireless communication system standard IEEE 802.16, the base station repeatedly transmits encoded data for the mobile station to detect the data even in a bad channel environment.
The mobile station (MS) estimates a channel response by using pilot subcarriers transmitted from the serving base station that transmits data. The MS detects the data by combining the repeated data subcarriers based on the estimated channel response.
As shown in FIG. 1, when the mobile station moves towards the border area between a serving cell (e.g., first base station) and neighboring cells (e.g., second and third base stations), the mobile station receives a signal from the first station and interfering signals from the second and third base stations.
However, a conventional data receiving method uses a limited repeat transmission rate without canceling an interfering signal from a neighboring base station, and therefore, this method needs to have severe interference in a cell boundary area solved.
When the mobile station has a plurality of receive antennas, the interfering signal from the neighboring base station can be cancelled by using a conventional interference cancellation method using multiple receive antennas.
However, it is not easy for a small mobile terminal to be equipped with multiple antennas. Even if the mobile station is equipped with several antennas, correlation between the antennas is high because of small antenna spacing, such that interference cancellation performance could be impaired. Therefore, a method and an apparatus for canceling an interference signal from a neighboring base station must be provided to a mobile terminal using a single antenna.